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_63905 ( "Title" text, "Series" text, "Director" text, "Production Num." real, "Release date" text )

### Question ###
Who was the director of the movie having a release date of 1934-09-15, an MM Series and a production number less than 6494?

### Accurate SQL ###

SELECT "Director" FROM table_63905 WHERE "Series" = 'mm' AND "Production Num." < '6494' AND "Release date" = '1934-09-15'