What Competition has an Event of 4x100 m relay and has the Time of 38.89?
CREATE TABLE "achievements" (
  "year" real,
  "competition" text,
  "venue" text,
  "position" text,
  "event" text,
  "time" text
);
SELECT "competition" FROM "achievements" WHERE "event"='4x100 m relay' AND "time"='38.89';