what is the average fa cup goals when the fa cup apps is 0, total goals is less than 1 and position is df?
CREATE TABLE "appearances_and_goals" (
  "name" text,
  "position" text,
  "league_apps" text,
  "league_goals" real,
  "fa_cup_apps" text,
  "fa_cup_goals" real,
  "league_cup_apps" real,
  "league_cup_goals" real,
  "total_apps" text,
  "total_goals" real
);
SELECT AVG("fa_cup_goals") FROM "appearances_and_goals" WHERE "fa_cup_apps"='0' AND "total_goals"<1 AND "position"='df';