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_23242968_1 ( written_by VARCHAR, production_code VARCHAR )

### Question ###
Who wrote the episode that had a production code of 3ajn20?

### Accurate SQL ###

SELECT written_by FROM table_23242968_1 WHERE production_code = "3AJN20"