List the rider for the doncaster handicap compeition.
CREATE TABLE "2008_09_season_as_a_three_year_old" (
  "result" text,
  "date" text,
  "race" text,
  "venue" text,
  "group" text,
  "distance" text,
  "weight_kg" text,
  "jockey" text,
  "winner_2nd" text
);
SELECT "jockey" FROM "2008_09_season_as_a_three_year_old" WHERE "race"='Doncaster Handicap';