What's the highest with a capacity of greater than 4,000 and an average of 615?
CREATE TABLE "attendances" (
  "team" text,
  "stadium" text,
  "capacity" real,
  "highest" real,
  "lowest" real,
  "average" real
);
SELECT MAX("highest") FROM "attendances" WHERE "average"=615 AND "capacity">'4,000';