Daily Kos writes, Want the scoop on hot races around the country? Get the digest emailed to you each weekday morning. Sign up here. Leading Off: • MA-Sen: Recently, I wondered about a discrepancy in the partisan composition of two MA-Sen Democratic primary polls: one from PPP, the other from MassINC. While the wording in MassINC's toplines PDF was a little confusing (they referred to all of their demographic categories as "questions"), it turns out that they were using party registration figures while PPP, as always, simply relied on partisan self-identification from its respondents. As you'd expect, these…