CREATE TABLE table_5600 ("Season" TEXT, "Regionalliga S\\u00fcd" TEXT, "Regionalliga West/S\\u00fcdwest" TEXT, "Regionalliga Nord" TEXT, "Regionalliga Nord-Ost" TEXT)

Which season had a Regionalliga Sud of Stuttgarter Kickers?
SELECT "Season" FROM table_5600 WHERE "Regionalliga S\u00fcd" = 'stuttgarter kickers'
SELECT "Season" FROM "table_5600" WHERE "Regionalliga S\u00fcd" = 'stuttgarter kickers'