user: Question: What is Name, when President is Khamtai Siphandon, and when Left Office is 1999?
Columns: ['Name', 'Took Office', 'Left Office', 'President', 'Party']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Sisavath Keobounphanh', '1996', '1998', 'Nouhak Phoumsavanh', "Lao People's Revolutionary Party"]
SQL:

assistant: SELECT "Name" FROM "Table" WHERE "President" = 'Khamtai Siphandon' AND "Left Office" = '1999';