tax query or
$args = array(
'post_type' => 'post',
'tax_query' => array(
'relation' => 'OR',
array(
'taxonomy' => 'category',
'field' => 'slug',
'terms' => array( 'quotes' ),
),
array(
'taxonomy' => 'post_format',
'field' => 'slug',
'terms' => array( 'post-format-quote' ),
),
),
);
$query = new WP_Query( $args );