The institutions that are covered by both are different. NCUA stands for National Credit Union Administration. This will be in charge of regulating and ensuring all of the federal credit unions that are based in the US of A. This was formed back in 1970 because of the increasing number of credit unions available.
The FDIC, on the other hand, is in charge of regulating the different bank accounts that are available. It also ensures the different bank accounts. The amount that will be covered by both will be the same at $250,000. It is best to know what is insured so that you will know what to expect.