CREATE TABLE table_15780 ("Week" FLOAT, "Date" TEXT, "Opponent" TEXT, "Result" TEXT, "Game site" TEXT, "Record" TEXT, "Attendance" TEXT)

Which week did the Seattle Seahawks have a record of 6-6?
SELECT AVG("Week") FROM table_15780 WHERE "Record" = '6-6'
SELECT AVG("Week") FROM "table_15780" WHERE "Record" = '6-6'