CREATE TABLE table_19759 ("Result" TEXT, "Date" TEXT, "Race" TEXT, "Venue" TEXT, "Group" TEXT, "Distance" TEXT, "Weight  ( kg ) " TEXT, "Jockey" TEXT, "Winner/2nd" TEXT)

When did the 55 kg participant race?
SELECT "Date" FROM table_19759 WHERE "Weight (kg)" = '55'
SELECT "Date" FROM "table_19759" WHERE "Weight (kg)" = '55'