CREATE TABLE table_name_20 (quantity VARCHAR2, year_s__of_manufacture VARCHAR2, class VARCHAR2)

what is the quantity when the year of manufacture is 1900 and the class is mc?
SELECT quantity FROM table_name_20 WHERE year_s__of_manufacture = "1900" AND class = "mc"
SELECT "quantity" FROM "table_name_20" WHERE "1900" = "year_s__of_manufacture" AND "class" = "mc"