Nitration of aniline in strong acidic medium also gives m-nitroaniline because:

Aniline is highly reactive and its $-{\text{NH}}_2$ group is $o,p$ -directing. However, nitration is carried out in a mixture of conc. ${\text{H}}_2{\text{SO}}_4$ and ${\text{HNO}}_3$. In this strongly acidic medium, aniline gets protonated to form the anilinium ion ($-{\text{NH}}_3^{+}$). The anilinium ion is a strong electron-withdrawing group and is meta-directing. This results in a significant amount (approx. $47\%$) of $m$ -nitroaniline being formed.