CREATE TABLE table_51551 ("5:00" TEXT, "6:00" TEXT, "7:00" TEXT, "8:00" TEXT, "10:00" TEXT, "11:00" TEXT)

What is the 6:00 with a 7:00 of mostly true stories: urban legends revealed, and a 10:00 with mysteryquest?
SELECT "6:00" FROM table_51551 WHERE "7:00" = 'mostly true stories: urban legends revealed' AND "10:00" = 'mysteryquest'
SELECT "6:00" FROM "table_51551" WHERE "10:00" = 'mysteryquest' AND "7:00" = 'mostly true stories: urban legends revealed'