I'll say! I saw it skip from 9-13-2007 to 1-21-2012. Four-and-a-half years! How did you guys even find this, considering that neither character has been relevant to the manga for at least 200+ chapters?!
Naruto battles, so point definitely Sasori. Also, he was far more level-headed in battle than Deidara, even as the battle turned against him--he's one of the few characters to not completely lose their shit (looking at you, Itachi >_>) in that situation. Furthermore, Deidara's explosives may have lacked the intensity to get through Sasori's initial defensive puppet, or even his "borrowed" Iron Sand techniques. A little sand mixed into Deidara's clay, and the fate is sealed.
There's no way Deidara wins the match-up.