user: Question: what is the earliest year when the author is Reki Kawahara?
Columns: ['Year', 'Character', 'Title', 'Author', 'Artist', 'Imprint']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [2005.0, 'I', 'Zaregoto series', 'Nisio Isin', 'Take', 'Kodansha Novels']
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Author" = 'Reki Kawahara';