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_54650 ( "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" text )

### Question ###
who was the director of the episode with production code ad1a26?

### Accurate SQL ###

SELECT "Directed by" FROM table_54650 WHERE "Production code" = 'ad1a26'