CREATE TABLE "schedule" (
  "race" text,
  "class_es" text,
  "length_duration" text,
  "circuit" text,
  "date" text
);

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

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

Question: What was the date of the race that lasted 6 hours?
SQL: SELECT "date" FROM "schedule" 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 "schedule" WHERE "circuit"='mazda raceway laguna seca';