How to do a duplicate search?

[11146]

I have a table:

Position | Parent position

ZDIR | DIR
RD | ZDIR
NO | RD
MS | NO

I know the position. I need to get a list of all the parent positions. For example, I know the position NO, as a result I should get a list [RD, ZDIR, DIR]. The search procedure is shown in the screenshot https://www.screencast.com/t/EWJwIeNJDg84

The maximum length of the result list is 5.