user: Question: What is the drainage basin when the reservoir suface is 6.14?
Columns: ['Reservoir', 'Basin', 'Location', 'Type', 'Height (m)', 'Length along the top (m)', 'Drainage basin (km²)', 'Reservoir surface (ha)', 'Volume (hm³)']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Alfilorios', 'Barrea', 'Ribera de Arriba', 'Embankment', '67.0', '171.7', '4.09', '52.0', '9.140']
SQL:

assistant: SELECT "Drainage basin (km²)" FROM "Table" WHERE "Reservoir surface (ha)" = '6.14';