user: Question: What year made has a Quantity made of 4?
Columns: ['Class', 'Wheel arrangement', 'Fleet number(s)', 'Manufacturer', 'Serial numbers', 'Year made', 'Quantity made', 'Quantity preserved']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives', 'Mallet and Simple Articulated Locomotives']
SQL:

assistant: SELECT "Year made" FROM "Table" WHERE "Quantity made" = '4';