Name the Away team score which has an Away team of st kilda, and a Crowd of 8157?
CREATE TABLE "group_2" (
  "home_team" text,
  "home_team_score" text,
  "away_team" text,
  "away_team_score" text,
  "ground" text,
  "date" text,
  "crowd" real
);
SELECT "away_team_score" FROM "group_2" WHERE "away_team"='st kilda' AND "crowd"=8157;