Table: rolex_sports_car_series
Columns: race
class_es
length_duration
circuit
date

Question: What is the length and duration of the race on April 19?
SQL: SELECT "length_duration" FROM rolex_sports_car_series WHERE "date" = 'april 19'

Question: What was the circuit had a race on September 20.
SQL: SELECT "circuit" FROM rolex_sports_car_series WHERE "date" = 'september 20'

Question: What was the date of the race that lasted 6 hours?
SQL: SELECT "date" FROM rolex_sports_car_series WHERE "length_duration" = '6 hours'

Question: What are the classes for the circuit that has the Mazda Raceway Laguna Seca race.
SQL: SELECT "class_es" FROM rolex_sports_car_series WHERE "circuit" = 'mazda raceway laguna seca'