Who was the home team in the match that had an away team of Convoy Sun Hei Team B?
CREATE TABLE "a_b_second_round" (
  "time" text,
  "home_team" text,
  "score" text,
  "away_team" text,
  "venue" text
);
SELECT "home_team" FROM "a_b_second_round" WHERE "away_team"='convoy sun hei team b';