Some question about a relay data-sheet
Right there on the front page it says: -


  PLC relay, consisting of base terminal block PLC-BSC.../1 IC/ACT with
  screw connection and pluggable miniature relay, for high inrush
  currents, for assembly on DIN rail NS 35/7.5, 1 N/O contact, input
  voltage 24 V DC, max. inrush current up to 130 A


And....


  What is limiting continuous current? Does that mean the relay will
  open if the continuous current exceeds 6A? I also don't underrated
  what it means for 10A in parenthesis. All 13 14 and BB bridged?? The
  sentence is not so clear.


The current is the continuous maximum current the contact is rated to take and, if you use all the terminals available for that contact, the continuous maximum current can be regarded as 10 amps.


  Can I use this relay for application rated for nominal 10A?


I would say that would be taking a risk that is too great.


  How come can this coil draw only 18mA at DC. I though coils have high
  resistance for AC voltages? Does that mean coil's DC resistance is
  1.3k? Data-sheet also does not mention any peak current for when the coil is de-energized. I thought the coil will have some high current
  during entering to off state.


24 volts and 18 mA is a coil power of 432 mW and sounds around about the right sort of level that you can expect froma relay of this type. Yes it will have a DC resistance of 1k333.

The peak current when the coil is disconnected will be 18 mA and you need to rate any back-emf protection devices for this current (not really a big deal of course). If you don't use a protection method then you might get a peak of thousands of volts that could destroy your transistor.