CREATE TABLE table_8807 ("Class" TEXT, "Wheel arrangement" TEXT, "Fleet number ( s ) " TEXT, "Manufacturer" TEXT, "Year made" TEXT, "Quantity made" TEXT, "Quantity preserved" TEXT)

What manufacturer made 6 and preserved 1?
SELECT "Manufacturer" FROM table_8807 WHERE "Quantity made" = '6' AND "Quantity preserved" = '1'
SELECT "Manufacturer" FROM "table_8807" WHERE "Quantity made" = '6' AND "Quantity preserved" = '1'