Game Site of hoosier dome, and a Result of l 7–31 involved what attendance?
CREATE TABLE "schedule" (
  "week" real,
  "date" text,
  "opponent" text,
  "result" text,
  "record" text,
  "game_site" text,
  "attendance" text
);
SELECT "attendance" FROM "schedule" WHERE "game_site"='hoosier dome' AND "result"='l 7–31';