What shows for miles [One Way] when the fans took 340?
CREATE TABLE "head_to_head" (
  "team" text,
  "miles_one_way" real,
  "home_result" text,
  "fans_brought" real,
  "away_result" text,
  "fans_took" text,
  "points_gained" real
);
SELECT AVG("miles_one_way") FROM "head_to_head" WHERE "fans_took"='340';