CREATE TABLE table_18865 ("Result" CLOB, "Date" CLOB, "Race" CLOB, "Venue" CLOB, "Group" CLOB, "Distance" CLOB, "Weight  ( kg ) " CLOB, "Time" CLOB, "Jockey" CLOB, "Winner/2nd" CLOB)

Who was the jockey at Rosehill and the weight was 57.5 kg?
SELECT "Jockey" FROM table_18865 WHERE "Venue" = 'Rosehill' AND "Weight (kg)" = '57.5'
SELECT "Jockey" FROM "table_18865" WHERE "Venue" = 'Rosehill' AND "Weight (kg)" = '57.5'