user: Question: When was the ship originally named Sachem finally decommissioned?
Columns: ['Name', 'Original name', 'Commissioned', 'Final decommission', 'Fate']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['USSChiwawa(AO-68)', 'Samoset', '24 December 1942', '6 May 1946', 'converted to laker, 1961; still in service']
SQL:

assistant: SELECT "Final decommission" FROM "Table" WHERE "Original name" = 'Sachem';