<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
<!--Generated by ThunderDome Portal - 5/6/2025 7:48:53 PM-->
<xsd:schema xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:stpr="http://xbrl.sec.gov/stpr/2024" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:dei="http://xbrl.sec.gov/dei/2024" xmlns:country="http://xbrl.sec.gov/country/2024" xmlns:sic="http://xbrl.sec.gov/sic/2024" xmlns:currency="http://xbrl.sec.gov/currency/2024" xmlns:exch="http://xbrl.sec.gov/exch/2024" xmlns:cyd="http://xbrl.sec.gov/cyd/2024" xmlns:sgc="http://www.sgc.com/20250508" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.sgc.com/20250508">
<xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
<xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/stpr/2024" schemaLocation="https://xbrl.sec.gov/stpr/2024/stpr-2024.xsd"/>
<xsd:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
<xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/dei/2024" schemaLocation="https://xbrl.sec.gov/dei/2024/dei-2024.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/country/2024" schemaLocation="https://xbrl.sec.gov/country/2024/country-2024.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/sic/2024" schemaLocation="https://xbrl.sec.gov/sic/2024/sic-2024.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/currency/2024" schemaLocation="https://xbrl.sec.gov/currency/2024/currency-2024.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/exch/2024" schemaLocation="https://xbrl.sec.gov/exch/2024/exch-2024.xsd"/>
<xsd:import namespace="http://xbrl.sec.gov/cyd-8k-sub/2024" schemaLocation="https://xbrl.sec.gov/cyd/2024/cyd-8k-sub-2024.xsd"/>

<xsd:annotation>
<xsd:appinfo>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="sgc-20250508_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="sgc-20250508_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="sgc-20250508_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
<link:roleType id="statement-document-and-entity-information" roleURI="http://www.sgc.com/20250508/role/statement-document-and-entity-information">
<link:definition xmlns="http://www.xbrl.org/2003/linkbase">000 - Document - Document And Entity Information</link:definition>
<link:usedOn>link:calculationLink</link:usedOn>
<link:usedOn>link:definitionLink</link:usedOn>
<link:usedOn>link:presentationLink</link:usedOn>
</link:roleType>
</xsd:appinfo>
</xsd:annotation>
<xsd:element abstract="true" id="sgc_DocumentAndEntityInformation" name="DocumentAndEntityInformation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
