It might not have been assigned yet, since procedurally it's part of a process by which a case is removed from the state court where it was first filed (in New York County, which is Manhattan) to a federal court, in this case the Southern District of New York. A state court case can be removed to a federal court if federal jurisdiction can be established, and here they are claiming that the Federal Tort Claims Act applies to Carroll´s claim because Trump was acting in his capacity as president. On that basis they are also moving to substitute the government as the defendant.
Once a case has been removed from state to federal court, the state court no longer has jurisdiction over the case. However, a federal court can remand the case to state court without any request by the plaintiff if the judge does not believe federal jurisdiction has been properly established by the defendant, and the plaintiff can also move to have the case remanded to state court if the plaintiff does not believe there is a basis for federal jurisdiction. I´m sure Carroll will oppose the removal and will try to get the case remanded to the state court.
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