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_21191496_1 (date VARCHAR, pole_position VARCHAR)

### Question ###
When michele pirro is the pole position what is the date?

### Accurate SQL ###

SELECT date FROM table_21191496_1 WHERE pole_position = "Michele Pirro"