Most probably(rather you can be sure), you'll get called for an interview in both these institutes.
56 marks will surely fetch you score above 650
Shortlisting criteria for IIIT Delhi in 2017----
0.5*GATE Score + 0.5 * UG percentage (both scaled to 100)
(eq. % for cgpa = (cgpa-0.5)*10)
effective cutoff was 65.9
For IIIT B > 620 for IT in 2nd round