Of the 27 NPC members in that photo, somewhere between 0 and 10 could be identified as social democrats (depending on where you draw the line with SMC, Groundwork, and Carnation- I would personally probably just say 4). I doubt any would self-ID as such.

A majority of active members- and therefore leadership- in DSA are Marxists. Red Star and much of Springs of Revolution are M-Ls, Marxist Unity Group are Ortho-Marxists, Reform & Revolution are Trotskyists, Bread & Roses are sorta post-Trotskyist, LSC are quasi-anarchists, even Groundwork ID as Marxists though they're on the right of the org.