When tus rosenberg is the oberpfalz what is the oberbayern b?
CREATE TABLE "southern_bavaria" (
  "season" text,
  "oberbayern_a" text,
  "oberbayern_b" text,
  "niederbayern" text,
  "schwaben" text,
  "oberpfalz" text
);
SELECT "oberbayern_b" FROM "southern_bavaria" WHERE "oberpfalz"='TuS Rosenberg';