What was the purse when the trainer was Aidan O'Brien?
CREATE TABLE table_name_21 (purse VARCHAR, trainer VARCHAR)
SELECT purse FROM table_name_21 WHERE trainer = "aidan o'brien"
### Context: CREATE TABLE table_name_21 (purse VARCHAR, trainer VARCHAR) ### Question: What was the purse when the trainer was Aidan O'Brien? ### Answer: SELECT purse FROM table_name_21 WHERE trainer = "aidan o'brien"