CREATE TABLE table_3139 ("Week" FLOAT, "Date" TEXT, "Kickoff" TEXT, "Opponent" TEXT, "Final score" TEXT, "Team record" TEXT, "Game site" TEXT, "Attendance" FLOAT)

What week had kickoff time at 6:00 p.m.?
SELECT MIN("Week") FROM table_3139 WHERE "Kickoff" = '6:00 p.m.'
SELECT MIN("Week") FROM "table_3139" WHERE "Kickoff" = '6:00 p.m.'