On what week were there 26,243 in attendance on September 21, 1969?
CREATE TABLE "season_schedule" (
  "week" real,
  "date" text,
  "opponent" text,
  "result" text,
  "attendance" real
);
SELECT COUNT("week") FROM "season_schedule" WHERE "date"='september 21, 1969' AND "attendance"<'26,243';