I assume this is for the flop?
To check for the player raising first in you can use: holdem_hand_player_statistics.flg_p_first_raise
To check for being the preflop aggressor (specifically, the last PF action being a raise) you can use: lookup_actions_p.action LIKE '%R'
However - if you only want hands where the player was the preflop aggressor you only need the second part. The above "action" string check says that the last action was to raise.
So you could make a new version of the stat that you're interested in and include that in the expressions. The
Tutorial: Custom Reports and Statistics explains how to make a new version of a stat.