CREATE TABLE table_959 ("Season" TEXT, "Regionalliga S\\u00fcd" TEXT, "Regionalliga West/S\\u00fcdwest" TEXT, "Regionalliga Nord" TEXT, "Regionalliga Nord-Ost" TEXT)

what's the season with regionalliga west/s dwest being arminia bielefeld
SELECT "Season" FROM table_959 WHERE "Regionalliga West/S\u00fcdwest" = 'Arminia Bielefeld'
SELECT "Season" FROM "table_959" WHERE "Regionalliga West/S\u00fcdwest" = 'Arminia Bielefeld'