The ornamental design for a watch, as shown and described.
FIG. 1.1 is a front perspective view of a watch showing my new design;
FIG. 1.2 is a front view thereof;
FIG. 1.3 is a back view thereof;
FIG. 1.4 is a left side view thereof;
FIG. 1.5 is a right side view thereof,
FIG. 1.6 is a top view thereof; and
FIG. 1.7 is a bottom view thereof.
The broken line showing of a watch face, hands, winding knob, and other minor elements is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design.