The calculated distance (air line) between Landau in der Pfalz and Duisburg is approximately 165 miles respectively 266 kilometers.
By car or train, the actual journey to Duisburg is certainly longer, as only the direct route (as the crow flies) between Landau in der Pfalz and Duisburg has been calculated here.
Air line (approximately)
266 kilometers
144 nautical miles