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_19392 ( "No. in series" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" real )

### Question ###
Who directed all the episodes that were written by aaron ehasz & john o'bryan?

### Accurate SQL ###

SELECT "Directed by" FROM table_19392 WHERE "Written by" = 'Aaron Ehasz & John O''Bryan'