The ornamental design for a turntable, as shown and described.
FIG. 1 is a perspective view of a turntable, showing my new design;
FIG. 2 is a front elevation view of the turntable shown in FIG. 1;
FIG. 3 is a back elevation view of the turntable shown in FIG. 1;
FIG. 4 is a left elevation view of the turntable shown in FIG. 1;
FIG. 5 is a right elevation view of the turntable shown in FIG. 1;
FIG. 6 is a top plan view of the turntable shown in FIG. 1; and,
FIG. 7 is a bottom plan view of the turntable shown in FIG. 1.
Those portions of the figures that are presented in broken lines merely illustrate the environment of the design and are not part of the claimed design.