first-child

<div class="ctr-1">
    <h3>Title1</h3>
    <div class="ctr-2">
        <h3>Title2</h3>
    </div>
</div>

hide first only
.ctr-1 > h3:first-child { display:none; }

hide two (first of a div)
.ctr-1 h3:first-child { display:none; }