CREATE TABLE table_203_754 (id NUMBER, "no." NUMBER, "player" CLOB, "position" CLOB, "career" CLOB, "date no. retired" CLOB)

how long was gretzky 's career ?
SELECT "career" - "career" FROM table_203_754 WHERE "player" = 'wayne gretzky'
SELECT "career" - "career" FROM "table_203_754" WHERE "player" = 'wayne gretzky'