user: Question: Which railway had the earliest build date and a disposal of "Scrapped 1941?"
Columns: ['Railway', 'Loco name', 'Build date', 'Wheels', 'Disposal']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['KESR', 'Tenterden', 1900.0, '2-4-0 T', 'Scrapped 1941']
SQL:

assistant: SELECT "Build date" FROM "Table" WHERE "Disposal" = 'Scrapped 1941';