CREATE TABLE table_203_874 (id NUMBER, "year" NUMBER, "competition" CLOB, "venue" CLOB, "position" CLOB, "event" CLOB, "notes" CLOB)

how long did it take to walk 50 km in the 2004 olympic games ?
SELECT "notes" FROM table_203_874 WHERE "event" = '50 km walk' AND "year" = 2004
SELECT "notes" FROM "table_203_874" WHERE "event" = '50 km walk' AND "year" = 2004