What is the height of the person whose position is Libero?
CREATE TABLE "team_roster_season_2011_2012" (
  "shirt_no" real,
  "nationality" text,
  "player" text,
  "birth_date" text,
  "height" real,
  "position" text
);
SELECT MAX("height") FROM "team_roster_season_2011_2012" WHERE "position"='libero';