Texas oil center (6)
I believe the answer is:
odessa
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">texas oil center</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for odessa that I've seen before include "Black Sea location" , "Port city of Ukraine" , "Ukrainian Black Sea port" , "Ukrainian location" , "Do seas come into Ukrainian city?" .)