What is the lwoest round of wild bill's fight night 21 at 5:00?
CREATE TABLE "mixed_martial_arts_record" (
  "res" text,
  "record" text,
  "opponent" text,
  "method" text,
  "event" text,
  "round" real,
  "time" text,
  "location" text
);
SELECT MIN("round") FROM "mixed_martial_arts_record" WHERE "time"='5:00' AND "event"='wild bill''s fight night 21';