user: Question: How many casualties were in the earthquake with an Unknown intensity and an epicenter in the Bouïra Province?
Columns: ['Date', 'Epicenter', 'Magnitude', 'Intensity', 'Casualties']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['May 1716', 'Algiers Province', 'Unknown', 'IX', '20,000 dead, thousands injured']
SQL:

assistant: SELECT "Casualties" FROM "Table" WHERE "Intensity" = 'Unknown' AND "Epicenter" = 'Bouïra Province';