What is the latest round for Pohang Steelers as the away team?
CREATE TABLE "fixtures" (
  "round" real,
  "date" text,
  "home_team" text,
  "score" text,
  "away_team" text,
  "attendance" real,
  "stadium" text
);
SELECT MAX("round") FROM "fixtures" WHERE "away_team"='pohang steelers';