Table: villa_season_1889
Columns: match
date
opponent
venue
result
attendance

Question: How many Attendance has a Opponent of west bromwich albion, and a Result of 3 – 3, and a Match larger than 20?
SQL: SELECT SUM("attendance") FROM villa_season_1889 WHERE "opponent" = 'west bromwich albion' AND "result" = '3 – 3' AND "match" > 20