In the match where the venue was arden street oval, what was the crowd attendance?
CREATE TABLE "round_9" (
  "home_team" text,
  "home_team_score" text,
  "away_team" text,
  "away_team_score" text,
  "venue" text,
  "crowd" real,
  "date" text
);
SELECT SUM("crowd") FROM "round_9" WHERE "venue"='arden street oval';