user: Question: what are all the date withdrawn for Twin Screw Ro-Ro Motorship
Columns: ['Ships name', 'Date entered service', 'Date withdrawn', 'Tonnage', 'Type of Ship']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Oranje Nassau', '27 August 1945', 'July 1954', 3053.0, 'Twin Screw Steamer']
SQL:

assistant: SELECT "Date withdrawn" FROM "Table" WHERE "Type of Ship" = 'Twin Screw Ro-Ro Motorship';