To display widget in blogger post only, follow the steps below,
1. Login to blogger
2. Go to Layout --> Edit HTML. Click on Expand Widget Template. Find widget. For example, adsense is placed with widget id HTML3.
<b:widget id='HTML3' locked='false' title='' type='HTML'>
3. Add code with bold text.
<b:widget id='HTML3' locked='false' title='' type='HTML'>
<b:includable id='main'><b:if cond='data:blog.pageType == "item"'><div style='float: left;padding:20px 0px 40px 0'><!-- only display title if it's non-empty --><b:if cond='data:title != ""'><h2 class='title'><data:title/></h2></b:if><div class='widget-content'><data:content/></div><b:include name='quickedit'/></div></b:if></b:includable></b:widget>
4. Save Template.