Lt. Cmdr. Benjamin Amdur got to see how much of a difference 50 years could make to nuclear submarines when he got to his new command. Amdur had previously served as the engineering officer of the Virginia-class submarine North Dakota, which will become the service’s newest sub when it is delivered in 2014, a Navy release said. On Tuesday, he became the officer-in-charge of the Nautilus, the world’s first nuclear-powered ship, during a ceremony in Groton, Conn. “I’m amazed every day at how far we have come in 50 years of nuclear power, and, as a credit to the original…