CREATE TABLE table_64250 ("Class" CLOB, "Railway number ( s ) " CLOB, "Quantity" FLOAT, "Year ( s )  of manufacture" CLOB, "Axle arrangement  (  UIC  ) " CLOB)

what is the quantity when the year of manufacture is 1900 and the class is mc?
SELECT "Quantity" FROM table_64250 WHERE "Year(s) of manufacture" = '1900' AND "Class" = 'mc'
SELECT "Quantity" FROM "table_64250" WHERE "Class" = 'mc' AND "Year(s) of manufacture" = '1900'