The ornamental design for a portion of a leg covering, as shown and described.
FIG. 1 is a front perspective view of a portion of a leg covering showing my new design.
FIG. 2 is a front view of the portion of a leg covering of FIG. 1.
FIG. 3 is a rear view of the portion of a leg covering of FIG. 1.
FIG. 4 is a left side view of the portion of a leg covering of FIG. 1.
FIG. 5 is a right side view of the portion of a leg covering of FIG. 1.
FIG. 6 is a top view of the portion of a leg covering of FIG. 1; and,
FIG. 7 is a bottom view of the portion of a leg covering of FIG. 1.
The broken lines in the figures are to show environment and form no part of the claimed design. The smaller broken lines immediately adjacent to the shaded area represent stitching that is not part of the claimed design.