Pablo Duarte is a Cuban expatriate and a member of the Cuban Revolutionary Council, a group formed with C.I.A. assistance in 1961 to overthrow Fidel Castro's communist government in Cuba. He's now living in New Bordeaux, but he still has connections in the movement, which is how Frank Pagani's smuggling operation got on his radar.
He tells Lincoln that Pagani's man Pops Holland runs the freight yard and does a lot of business with Havana. Since losing River Row, Pops has had to resort to air drops, but they move them around, so Lincoln will have to find out where they're being coordinated from.
After Lincoln puts an end to Pops' operations, Pablo is pleased to inform him that they've managed to piss off both the communists and the Marcanos. Word on the street is that Pops Holland is seriously screwed thanks to Lincoln, and Pagani ordered Pops to come back to the freight yard until he's dealt with.