user: Question: What is the manufacturer serial number of the 1963 withdrawn year?
Columns: ['Wheel arrangement', 'Manufacturer Serial numbers', 'Year introduced MRWA', 'Quantity made', 'Quantity preserved', 'Year(s) withdrawn']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Steam locomotives', 'Steam locomotives', 'Steam locomotives', 'Steam locomotives', 'Steam locomotives', 'Steam locomotives']
SQL:

assistant: SELECT "Manufacturer Serial numbers" FROM "Table" WHERE "Year(s) withdrawn" = '1963';