The ornamental design for a pergola, as shown and described.
FIG. 1 is a perspective view of a pergola showing the claimed design, wherein the break lines indicate intermediate length;
FIG. 2 is a side elevation view thereof;
FIG. 3 is a front elevation view thereof, wherein the break lines indicate intermediate length;
FIG. 4 is a rear elevation view thereof, wherein the break lines indicate intermediate length;
FIG. 5 is a top elevation view thereof, wherein the break lines indicate intermediate length; and,
FIG. 6 is a bottom elevation view thereof, wherein the break lines indicate intermediate length.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines of the drawings are for illustrative purposes only and form no part of the claimed design.