What was the lowest week at Ralph Wilson Stadium on October 7, 2001?
CREATE TABLE "schedule" (
  "week" real,
  "date" text,
  "opponent" text,
  "result" text,
  "record" text,
  "game_site" text,
  "attendance" text
);
SELECT MIN("week") FROM "schedule" WHERE "game_site"='ralph wilson stadium' AND "date"='october 7, 2001';