CREATE TABLE table_17012 ("Institution" TEXT, "Location" TEXT, "Founded" FLOAT, "Type" TEXT, "Enrollment" FLOAT, "Nickname" TEXT, "Joined" FLOAT, "Left" FLOAT, "Current Conference" TEXT)

What year did the school from mars hill, north carolina join?
SELECT "Joined" FROM table_17012 WHERE "Location" = 'Mars Hill, North Carolina'
SELECT "Joined" FROM "table_17012" WHERE "Location" = 'Mars Hill, North Carolina'