CREATE TABLE table_37669 ("Pos." FLOAT, "Mark" TEXT, "Athlete" TEXT, "Venue" TEXT, "Date" TEXT)

On which date was the position less than 4 at Piraeus?
SELECT "Date" FROM table_37669 WHERE "Pos." < '4' AND "Venue" = 'piraeus'
SELECT "Date" FROM "table_37669" WHERE "Pos." < '4' AND "Venue" = 'piraeus'