before week 12 what was the attendance on 1983-11-21?
CREATE TABLE "schedule" (
  "week" real,
  "date" text,
  "opponent" text,
  "result" text,
  "game_site" text,
  "attendance" real
);
SELECT SUM("attendance") FROM "schedule" WHERE "date"='1983-11-21' AND "week"<12;