Whatever the meaning of "La" is, it is part of the name, so it will stay. Same idea for surnames that start with "de", like Charles de Gaulle.
French: C'est une citation de De Gaulle.
German: Das ist ein Zitat von Von Neumann.
Both correct, but one would probably add "Charles" or "John" between the two 'de' or 'von' just to break them up.