CREATE TABLE table_55229 ("Event" TEXT, "Record" TEXT, "Athlete" TEXT, "Nationality" TEXT, "Date" TEXT)

What was the date of the discus throw for Bulgaria?
SELECT "Date" FROM table_55229 WHERE "Nationality" = 'bulgaria' AND "Event" = 'discus throw'
SELECT "Date" FROM "table_55229" WHERE "Event" = 'discus throw' AND "Nationality" = 'bulgaria'