We're only three days and 42 games in, but the national League actually leads the Interleague series thus far. Right now the NL sits at a 22-20 record- granted with 188 runs scored and 209 runs allowed it may be a bit of an illusion. Those run totals would more likely suggest just a 19-23 record for the NL.
At NL parks, the National League teams are 12-9 with an expected 10-11 based on the runs scored and allowed. At AL parks they're at 10-11 with an expected 9-12.