hook for loading page

Filter the_content and check if is_page( 'jobs' ) is TRUE:

add_filter( 'the_content', 'get_scrapy_scraped' );

function get_scrapy_scraped( $content )
{
    global $wpdb;

    if ( ! is_page( 'jobs' ) )
        return $content;

    $table_name    = $wpdb->prefix . "Careers";
    $retrieve_data = $wpdb->get_results( "SELECT * FROM $table_name" );

    if ( ! $retrieve_data )
        return $content;

    $table="<table><tr>
    <th>Job Name</th>
    <th>Location/Dept</th>
    <th>Complete Info</th>
    <th>Application Link<th>
    </tr>";

    foreach ( $retrieve_data as $row )
    {
        $table .= "<tr>
            <td>{$row->Job_Name}</td>
            <td>{$row->Job_Department}</td>
            <td>{$row->Job_Link_Info}</td>
            <td>{$row->Job_Link_Apply}</td>
            </tr>";
    }

    $table .= "</table>";

    return $table . $content;
}