CREATE TABLE table_11713303_2 (replaced_by VARCHAR(255), date_of_appointment VARCHAR(255), manner_of_departure VARCHAR(255))
How many have been replaced where the appointment date is 10 December 2007 and the manner of departure is quit?
    
SQL: SELECT COUNT(replaced_by) FROM table_11713303_2 WHERE date_of_appointment = "10 December 2007" AND manner_of_departure = "Quit"