What constellation is there in the center of the Milky Way?

The center of the Milky Way is Sagittarius (also known as Sagittarius), declination 17h46m and declination -28d56.

It is impossible to talk about any constellation in the galactic center. Constellation is only the apparent distribution of stars in the starry sky as seen by the earth people. In fact, some of the stars in the same constellation are close to us, and some are far away from us. Take Orion for example. Betelgeuse is 427 light years away, while Betelgeuse is 773 light years away.