How many League Cup goals correspond to 3 FA Cup Goals and a total over 15 for Chesterfield?
CREATE TABLE "third_division" (
  "scorer" text,
  "club" text,
  "league_goals" text,
  "fa_cup_goals" real,
  "league_cup_goals" text,
  "total" real
);
SELECT "league_cup_goals" FROM "third_division" WHERE "total">15 AND "fa_cup_goals"=3 AND "club"='chesterfield';