The ornamental design for a tablelegtube, as shown and described.
FIG. 1 is a front right perspective view of a table leg tube of my new design;
FIG. 2 is a left front perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a left side elevational view thereof, a right side elevational view being identical;
FIG. 5 is a front elevational view thereof, a rear elevational view being identical; and,
FIG. 6 is a bottom plan view thereof.
The table leg tube is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.