to have the same functionality in the championship you will have to change code in another file (same change)
<joomla-installation>/components/com_masterleaguepro/views/minileaguematches/tmpl/default.php

lines 57~59
Code:
<td><?php
	echo "<input type='text' name='jform[home_team_score][".$match->match_id."]' value='".$match->home_prediction."' min='0'/> - <input type='text' value='".$match->away_prediction."' name='jform[away_team_score][".$match->match_id."]' min=0 />";
?></td>
to

Code:
<td>
	<select name='jform[home_team_score][<?php echo $match->match_id;?>]' style='max-width: 110px;'>
		<option value=''>Select Score</option>
		<?php for($sc=0;$sc<=20;$sc++): ?>
			<option value='<?php echo $sc; ?>'<?php echo $sc==$match->home_prediction?" selected='selected'":""; ?>><?php echo $sc; ?></option>
		<?php endfor;?>
	</select>




	-




	<select name='jform[away_team_score][<?php echo $match->match_id;?>]'  style='max-width: 110px;'>
		<option value=''>Select Score</option>
		<?php for($sc=0;$sc<=20;$sc++): ?>
			<option value='<?php echo $sc; ?>'<?php echo $sc==$match->away_prediction?" selected='selected'":""; ?>><?php echo $sc; ?></option>
		<?php endfor;?>
	</select>
</td>