CREATE TABLE "calendar_winners" (
  "round" text,
  "circuit" text,
  "date" text,
  "class_a_winner" text,
  "class_b_winner" text,
  "class_c_winner" text,
  "class_d_winner" text
);

Question: Who was the Class A winner when the Class C winner was David Haynes?
SQL: SELECT "class_a_winner" FROM "calendar_winners" WHERE "class_c_winner"='David Haynes';

Question: Who was the Class C winner in round 8?
SQL: SELECT "class_c_winner" FROM "calendar_winners" WHERE "round"='8';

Question: Who was the Class D winner in round 6?
SQL: SELECT "class_d_winner" FROM "calendar_winners" WHERE "round"='6';

Question: What was the circuit in round 2?
SQL: SELECT "circuit" FROM "calendar_winners" WHERE "round"='2';