user: Question: Which Week has a Result of l 21-19?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 3, 2000', 'San Francisco 49ers', 'W 36-28', '54,626']
SQL:

assistant: SELECT "Week" FROM "Table" WHERE "Result" = 'l 21-19';