Table schema:
CREATE TABLE table_name_98 (league_goals INTEGER, name VARCHAR, league_cup_apps VARCHAR, fa_cup_goals VARCHAR, position VARCHAR)

Question: What is the League Goals when the FA Cup Goals are 0, position is mf, League Cup Apps of 0, and name is Ben Thornley?
SQL: SELECT AVG(league_goals) FROM table_name_98 WHERE fa_cup_goals = "0" AND position = "mf" AND league_cup_apps = "0" AND name = "ben thornley"