There's an episode in TNG (I think it may even be a multi-part episode) where Romulans and the Federation are having some kind of stand-off, and Picard is ordered to take command of a number of Federation ships to act as a blockade against the Romulans. All of his command staff are assigned a ship, except for Data. When Data makes an inquiry about this discrepency, Picard relents, and gives Data command of a ship.
On the ship itself, one of Data's crewmen attempt to be reassigned, not wanting to be under the command of an Android. Data refuses his request, and the crewman continues to doubt Data's ability. In the end, it is Data's ability to read a ruse by the Romulans to break the blockade that prevents it from being broken.
This episode(s?) also included a Romulan Tasha Yar.
What is the name of this episode/these episodes?