FIG. 1 is a front elevation view of a level, showing my new design; FIG. 2 is a rear elevation view thereof; FIG. 3 is a left-side elevation view thereof; FIG. 4 is a right-side elevation view thereof; FIG. 5 is a top plan view thereof; FIG. 6 is a bottom plan view thereof; and, FIG. 7 is a perspective view thereof. The broken lines depict portions of the level that form no part of the claimed design.