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_73415 ( "Season no." real, "Series no." real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" real, "U.S. Viewers (millions)" text )

### Question ###
which is the biggest production code?

### Accurate SQL ###

SELECT MAX("Production code") FROM table_73415