What round was the player Ty Lawson with a pick earlier than 18?
CREATE TABLE "team_players_drafted_into_the_nba" (
  "year" real,
  "round" real,
  "pick" real,
  "player" text,
  "nba_club" text
);
SELECT AVG("round") FROM "team_players_drafted_into_the_nba" WHERE "player"='ty lawson' AND "pick"<18;