If I understand your question correctly, you can use
Or
operator. Something like
"LastName Like '%{0}%' Or FirstName Like '%{1}%'"
If you want to embed space to the condition for first and last name consider something like
"LastName Like '% {0}%' Or FirstName Like '%{1} %'"
For information about possible expressions, see
https://msdn.microsoft.com/en-us/library/system.data.datacolumn.expression(v=vs.110).aspx[
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