CREATE TABLE "singles_18_8" (
  "edition" text,
  "round" text,
  "date" text,
  "surface" text,
  "opponent" text,
  "result" text
);

Question: What surface was the April 24, 2003 match played on?
SQL: SELECT "surface" FROM "singles_18_8" WHERE "date"='april 24, 2003';