I am using Inkscape 0.92 on Ubuntu 18.04. When I try to draw a circle or an oval the object draws as shown below.
This is not a color, transparancy, or draw order issue. Do I need to reinstall Inkscape to an earlier version?
Look at the Tool Controls Bar along the top, for the Ellipse Tool.
Hit the "Whole Ellipse" button shown highlighted in red here
Also make sure the Ellipse has a coloured fill (not white) or a stroke (not white) applied, otherwise it will be invisible! You can change the fill or stroke in the Fill and Stroke Panel (Shift+Ctrl+F).
Note that 0.92 is old, although that isn't the source of your problem. The most recent version of Inkscape to date is 1.0.1