Оба кода верны, но семантически верны?
Имеет <p>
<ol>
<li>
<h2>heading level 2</h2>
<p>
some long text here some long text here some long text
here some long text here some long text here some long
text here some long text here some long text here
</p>
</li>
</ol>
Это без <p>
<ol>
<li>
<h2>heading level 2</h2>
some long text here some long text here some long
text here some long text here some long text here
some long text here some long text here some long text here
</li>
</ol>