user: Question: Who were the developers for Portal?
Columns: ['Year', 'Game', 'Genre', 'Platform(s)', 'Developer(s)']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2007.0, 'Portal', 'Puzzle , first-person shooter , science fiction', 'Xbox 360 , PlayStation 3 , Windows', 'Valve Corporation']
SQL:

assistant: SELECT "Developer(s)" FROM "Table" WHERE "Game" = 'Portal';