user: Question: Which Casualties have a Hostile Nature of incident and Circumstances of Mortar attack?
Columns: ['Date', 'Location', 'Nature of incident', 'Circumstances', 'Casualties']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2004-01-28', 'Kabul', 'Hostile', 'Bomb attack', '2 WIA']
SQL:

assistant: SELECT "Casualties" FROM "Table" WHERE "Nature of incident" = 'Hostile' AND "Circumstances" = 'Mortar attack';