Can you tell me the lowest Crowd that has the Away team of melbourne tigers?
CREATE TABLE "semi_finals" (
  "date" text,
  "home_team" text,
  "score" text,
  "away_team" text,
  "venue" text,
  "crowd" real,
  "box_score" text,
  "report" text
);
SELECT MIN("crowd") FROM "semi_finals" WHERE "away_team"='melbourne tigers';