Which year has a Main of Eintracht Frankfurt and Hessen of FSV Mainz 05?
CREATE TABLE "1928_to_1933" (
  "year" real,
  "main" text,
  "hessen" text,
  "rhein" text,
  "saar" text
);
SELECT "year" FROM "1928_to_1933" WHERE "main"='eintracht frankfurt' AND "hessen"='fsv mainz 05';