I did not account for the mass retardation of the X to think I could have possibly meant anything other than coaches in the SEC at their current jobs. Mea culpa.
In that case, Orgeron has Mullen beat. But still not Saban, because then he's been in the SEC since 2000.
It wasn't retardation, you said SEC tenured which was why I clarified with "if you are saying SEC tenured" and Orgeron would be 6 (4 Ole Miss, 2 LSU) years but not concurrently. Mullen was 9 years, Saban is 11 at bama, 5 at LSU so 16 but again not concurrently. Gus is of course 5.
I think it makes sense to leave Mullen in the equation though as his SEC tenure would occur from one season to the next.
Now Tenure with the same school, you are correct.