CREATE TABLE table_66904 ("Territory" TEXT, "Broadcaster" TEXT, "Channel" FLOAT, "Launched" TEXT, "Closed" TEXT)

When did channel 83 in singapore launch?
SELECT "Launched" FROM table_66904 WHERE "Territory" = 'singapore' AND "Channel" = '83'
SELECT "Launched" FROM "table_66904" WHERE "Channel" = '83' AND "Territory" = 'singapore'