John,
Was his pension from the Federal Government (Union ? ) or from Tennessee ( Confederate ? ) On the soldier search site I couldn't find a Joseph Jones in either the Union or Confederate 13th from Tennessee. Co.L of the Union 8th Tn Cav. started out as a company in the 10th East Tennessee Cav.organized at Rogersville on Oct 17,1863 by a Capt David W. Brown. There is also listed a Joseph Jones in the Union 3rd Tn. Mtd. Inf. I had ancestors in both the 8th cav. ( Co.G Sullivan County ) and 3rd Mtd ( Co.F.Greene County Confederate deserter ) May be just a mistake on his marker.
Glenn