CREATE TABLE table_12639 ("Rnd." FLOAT, "Pick #" TEXT, "NFL team" TEXT, "Pos." TEXT, "College" TEXT, "Conf." TEXT)

What is Northern Colorado's Rnd.?
SELECT "Rnd." FROM table_12639 WHERE "College" = 'northern colorado'
SELECT "Rnd." FROM "table_12639" WHERE "College" = 'northern colorado'