JSFiddle - React, Tailwind, and code Playground

HTML

<select class="text_select" id="field_6" name="field_6">    
<option value="- Select -">- Select -</option>  
<option value="Option One">Option One</option>  
<option value="Option Two">Option Two</option>  
<option value="Option Three">Option Three</option>  
</select>

<label class="form_field">Your selected <span id="aggregator_name"></span>?</label>

JavaScript

$(document).ready(function() {
    $("#field_6").change(function() {
        $('#aggregator_name').html($(this).val());
    }).change();
});