Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_21649285_2 (runner_s__up VARCHAR, margin_of_victory VARCHAR)

### Question ###
Who was the runner up when the won by 4 strokes?

### Accurate SQL ###

SELECT runner_s__up FROM table_21649285_2 WHERE margin_of_victory = "4 strokes"