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_20613292_1 ( production_code VARCHAR, written_by VARCHAR, directed_by VARCHAR )

### Question ###
What's the production code of the episode written by Kirker Butler and directed by Dan Povenmire?

### Accurate SQL ###

SELECT production_code FROM table_20613292_1 WHERE written_by = "Kirker Butler" AND directed_by = "Dan Povenmire"