if(!mysql_affected_rows() >= 1)
Does not work with SELECT, only INSERT, UPDATE, REPLACE or DELETE.
Also you're trying to loop twice.
The function you're looking for is mysql_num_rows:
<?php
$connect=mysql_connect("localhost","root","");
$db_selected = mysql_select_db("ong_assessment", $connect)
$query = "SELECT Agent_ID,Address,Bedrooms,Price FROM suburbs";
$result = mysql_query($query) or die(mysql_error());
if(!mysql_num_rows($result) >= 1)
{
echo 'There are no entries inside the database';
}
else
{
echo "<table>";
while($row = mysql_fetch_assoc($result))
{
echo '<tr><td>'. $row['Agent_ID'].'</td>';
echo '<td>'. $row['Address'].'</td>';
echo '<td>'. $row['Bedrooms'].'</td>';
echo '<td>'. $row['Price'].'</td></tr>';
}
echo '</table>';
}
?>