The ornamental design for a bag having bottomcenter handle, as shown and described.
FIG. 1 is a front perspective view of a bag having bottom center handle, showing our new design.
FIG. 2 is a front elevation view thereof.
FIG. 3 is a rear elevation view thereof.
FIG. 4 is a right or left side view thereof.
FIG. 5 is a top view thereof.
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a detail view of the bottom center handle area of the bag of FIG. 1.
The broken line showing of a rectangle is included for the purpose of illustrating the detail of the bottom center handle of the bag and forms no part of the claimed design.