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_23057 ( "Series #" real, "Episode #" real, "Title" text, "Written by" text, "Directed by" text, "Viewers" real, "Original airdate" text )

### Question ###
What is the series number for the episode written by Kristen Dunphy and David Ogilvy?

### Accurate SQL ###

SELECT MAX("Series #") FROM table_23057 WHERE "Written by" = 'Kristen Dunphy and David Ogilvy'