The ornamental design for a distance piece, as shown and described.
FIG. 1 is a top, front, and side perspective view of a distance piece showing my new design; the rear and other side views being mirror images thereof.
FIG. 2 is a bottom, front, and side perspective view thereof; the rear and other side views being mirror images thereof; and,
FIG. 3 is a top plan view thereof; the bottom plan view being a mirror image thereof.