user: Question: Who were the victims of the US ship that sank in the Mississippi River near Memphis?
Columns: ['Estimate', 'Name', 'Nat.', 'Ship Type', 'Principal victims', 'Where sunk', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1300–1900', 'SS Sultana', 'US', 'Transport Steamboat', 'Union POWs formerly held by the Confederate Army', 'Mississippi River near Memphis', 'April 27, 1865']
SQL:

assistant: SELECT "Principal victims" FROM "Table" WHERE "Nat." = 'US' AND "Where sunk" = 'Mississippi River near Memphis';