What year was Jeff Mullins?
CREATE TABLE "winners_of_the_colonial_turf_cup" (
  "year" real,
  "winner" text,
  "jockey" text,
  "trainer" text,
  "owner" text,
  "distance_miles" text,
  "time" text
);
SELECT MIN("year") FROM "winners_of_the_colonial_turf_cup" WHERE "trainer"='jeff mullins';