Table schema:
CREATE TABLE table_name_80 (fa_cup_goals INTEGER, position VARCHAR, fa_cup_apps VARCHAR, total_goals VARCHAR)

Question: what is the average fa cup goals when the fa cup apps is 0, total goals is less than 1 and position is df?
SQL: SELECT AVG(fa_cup_goals) FROM table_name_80 WHERE fa_cup_apps = "0" AND total_goals < 1 AND position = "df"