CREATE TABLE table_25391981_20 (weekly_rank VARCHAR(255), share VARCHAR(255), original_airdate VARCHAR(255))
What is the weekly rank of the episode with a 14 share whose original airdate was April 20, 2010? 
    
SQL: SELECT weekly_rank FROM table_25391981_20 WHERE share = "14" AND original_airdate = "April 20, 2010"