Table: barbarossa_ships
Columns: ship
tonnage
builder
original_operator
fate

Question: What is the fate for the Bremen ship?
SQL: SELECT "fate" FROM barbarossa_ships WHERE "ship" = 'bremen'

Question: Who is the original operator for the AG Vulcan builder and the Prinzess Irene ship?
SQL: SELECT "original_operator" FROM barbarossa_ships WHERE "builder" = 'ag vulcan' AND "ship" = 'prinzess irene'

Question: What is the Tonnage that has builder AG Vulcan, and the original operator NDL, and the ship, Prinzess Irene?
SQL: SELECT "tonnage" FROM barbarossa_ships WHERE "builder" = 'ag vulcan' AND "original_operator" = 'ndl' AND "ship" = 'prinzess irene'