First of all, the melodies use similar pitches. For the sake of comparison, in the examples below the "Parade of the Ewoks" has been transposed to match the "March". The red lines, then, indicate identical pitches. Both the Williams and the Prokofiev use A flat frequently, and play with the note C - sometimes it's C natural, other times it's C flat.
The strongest relationship, however, is not in pitches nor rhythm but rather in character - both are rather ridiculous marches (the score for "Parade of the Ewoks" is marked "A la marcia") that share tempi and border on absurdity. Orchestrationally, too, the comedy of both is heightened by the prominent use of the piccolo.
While not as evident as some other Star Wars borrowings, there are undeniable similarities between "Parade of the Ewoks" and the march from The Love of Three Oranges. With that in mind, it's a pretty safe bet that George Lucas included the latter on his temp track for Return of the Jedi.